1. Field of the Invention
The present invention relates to a hybrid switching method of spindle motor of optical disc drive and, more particularly, to a hybrid switch method for use a feedback RF signal of the disc of a spindle motor of an optical disc drive.
2. Description of Related Art
A disc data track is distributed of the spiral-shaped track. Every unit data is the same distant from inner to outer method to record on the disc. So, the every cycle disc data quality is directly proportional with the disc radius. According to the present spindle motor control method have two kind of the write/read mode, one is Constant Linear Velocity (CLV) and another is Constant Angular Velocity (CAV).
In tradition CLV control method mode and fix transmit rate, the rotate speed is inversely proportional with disc radius. FIG. 1a shows a spindle motor speed and position relationship on the CLV mode. And FIG. 1b shows a data transmit rate and position relationship on the CLV mode. The CLV transmit mode was limited to easy by motor speed. To use the CLV method, will need to high rotate speed motor to prove data transmit rate and create cost up. Meanwhile, the motor rotate speed is maximum in the CLV mode and creates the motor power lose biggest. These questions will more severity on the high optical disc drive, especially.
In tradition CAV control method mode and fix rotate speed, the transmit rate is directly proportional with disc radius. FIG. 2a shows data rate and position relationship on the CAV mode. And FIG. 2b shows a spindle motor speed and position relationship on the CAV mode. Use the CAV mode control motor will meet to data quality follow pick-up head position to change question. When the CAV in the outside, the transmit rate will faster. But, when the CAV in the inside, the transmit rate will slower.
In conclusion, according to prior method will have below disadvantage:
(1) Only the CLV write/read method, the inner/outside motor speed is not the same. To create high motor power lose and to long search track time. The data transmit rate will be limit to lower for inner motor rotate speed.
(2) Only the CAV write/read method, the motor rotate speed is a fixed value. So, the motor power lose is lower and search track time is shorter. But, the data transmit rate is directly proportional with the disc radius. Consequently, the average data transmit rate will be limit to lower by outside data transmit rate.